1. Field of the Invention
The present invention relates to a camera module assembled by using a connector, and more particularly, to a camera module capable of electrically connecting a flexible printed circuit board and a main substrate, which supply power to a lens driving actuator, through a connector.
2. Description of the Related Art
In general, a compact camera module (CCM) is manufactured in a small size and applied to various IT devices of mobile communication devices including a camera phone, a PDA, and a smart phone. Recently, the launch of devices with small camera modules has been gradually increased.
This camera module has been manufactured by using an image sensor such as a CCD or a CMOS as a main component. Images of an object are condensed by the image sensor and stored as data in a memory of a device, and the stored data are displayed as images through a display medium such as an LCD or a PC monitor in the device.
Especially, in recent times, a camera module with additional functions such as an autofocus (AF) function and a zoom function is required to meet various needs of consumers. These additional functions are obtained by embedding an actuator in the camera module to drive a lens up and down.
At this time, in the camera module with the additional functions, generally, since a high pixel image sensor is mounted on a main substrate, and various passive elements and IC chips are mounted around the image sensor, an optimal circuit design of the main substrate is important. At this time, a design of a connection portion with the main substrate for supplying power to the actuator is important.
However, as described above, since the various elements including the passive elements, as well as the image sensor are simultaneously mounted on the main substrate, there is a problem that it is very difficult to secure an electrical connection between the actuator and the main substrate, that is, design freedom of terminal connection.
Meanwhile, in case that a pitch and a size of pads for connecting the actuator to the main substrate on which the image sensor is mounted are sufficient, a wire bonding method with high mechanical bonding strength may be employed. However, it is difficult to miniaturize the camera module due to size increase of the main substrate, and there are problems of circuit failure due to the size of the pad formed on the main substrate and secondary circuit failure in assembly of a socket and the main substrate characterized in that it is mainly assembled in a socket coupling type.
In order to solve these problems, an electrical connection between the pads for connecting the actuator and the main substrate is formed by minimizing an interval between the pads and coating solder paste or conductive epoxy on a boundary between the pads, but it has been pointed that it is difficult to design a process condition for the connection between the adjacent pads and to reliably maintain stable connection quality of a connection portion between the pads. Especially, in case of the conductive epoxy, since there is a difference of mechanical strength in a bonding portion according to wettability with a surface of the pad, that is, a coating target, and a coating area, there is a disadvantage in that an additional reinforcing process is required to maintain uniform curing strength.